<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        var arr = [1,8,42,51,14,82,4];
        // 求这个数组元素和的平均值
        var sum = 0;
        for(var i = 0; i< arr.length; i++){
            sum+=arr[i];
        }
        var arg = sum/arr.length;
        console.log(arg);
    </script>
</body>
</html>